在正累积粒度特性曲线上，当物料中粗粒级占多数时，曲线是（）形。
A.凹
B.凸
C.接近直接
D.以上都不对
参考答案：B
The nurse is administering warfarin (Coumadin) to a client with deep vein thrombophlebitis. Which laboratory value indicates warfarin is at therapeutic levels ？（）
A．Partial thromboplastin time (PTT) to 2 times the control.
B．Prothrombin time (PT) to 2 times the control.
C．International normalized ratio (INR) of 3 to 4.
D．Hematocrit of 32%.
to 2 times the control.